In a much anticipated ruling, the Supreme Court struck down major parts of Arizona's immigration law, allowing the federal government and not the state to set immigration policy. The controversial "show me your papers" clause, however, was left in.

Justice Kennedy wrote the majority opinion.

The National Government has significant power to regulate immigration. Arizona may have understandable frustrations with the problems caused by illegal immigration while that process continues, but the State may not pursue policies that undermine federal law.

The aspects of the law that were struck down include police arresting illegal immigrants without a warrant for "probable cause," making it a state crime for unauthorized immigrants to not carry registration papers, and forbidding unauthorized immigrants to solicit or do work.

Justice Scalia wrote the dissenting opinion.

If securing its territory in this fashion is not within the power of Arizona, we should cease referring to it as a sovereign State.

He was backed by Justices Alito and Thomas.

Regardless, "show me your papers" remains a statewide policy, despite the fact that Arizona police worry it badly damages relations with the Latino community. Officers can still stop and demand papers from anyone who they "reasonably suspect" is an illegal immigrant.

According to Tuscon chief of police Roberto Villasenor, this puts police in a precarious position. They must struggle to uphold the law while facing criticism from both sides.

Under the supreme court decision, police departments in Arizona must enforce section 2b, and no one respects the authority of the courts more than police chiefs, so we will do our best to enforce the law. But we are in uncharted territory on this issue. So police in Arizona may be sued by people who believe they are not aggressive enough in enforcing the law — or by others who believe that police are being too aggressive or are engaging in racial profiling.

In response to the Supreme Court's decision, President Obama said he was pleased with the outcome but still concerned about the ambiguity of the "reasonable suspicion" clause.

Meanwhile Governor Jan Brewer claimed the ruling as a victory, noting that the measure at the "heart" of the legislation remains intact. Yes, the cold, dark, "show me your papers" clause heart will keep thumping along. And as it goes on, Arizona can look forward to the continued civil rights lawsuits that come with it.

ACLU's executive director Anthony Romero put it bluntly — "If you are a state that wants to try to enact these laws, we will see you in court."